1. Field Of The Invention
The apparatus of the present invention relates to metal roofing. More particularly, the present invention relates to a clip, which is supported on its base to a joist or purlin, the upper portion of which supports metal roofing panels, while allowing transnational and/or sliding movement of the panels relative to the stationary base or purlin.
2. General Background
In the construction of buildings, one of the more common types of construction are the prefabricated buildings constructed of metal components. Such buildings are usually constructed of a metal frame, where metal panels of metal such as tin or other type of light-weight metal is laid edge-to-edge in order to form a continuous walled and roofed structure. In the area of the roof structure, due to the need to exclude moisture coming in through the top of the building, the roof panels are normally formed of overlapping sections, then formed into a seam by a mechanical roll former, to increase the strength and flexibility of the roof. Joist or purlin are positioned across the roof rafters, supported by the rafters. In view of the fact that the purlin would normally extend along the longest part or length of a metal building, the roofing system formed of the seamed panels is installed on the purlin, in such a manner as to form the standing seam between the panels.
This type of construction therefore lends itself to employing a particular type of device or clip for attaching the panels to the purlin at areas along the length of each of the panels. This can be easily done through the use of stationary clips, where an upper portion of the clip is clipped into the seam between the panels, and the clip is rigidly attached to the top of the purlin. However, one of the drawbacks to this type of construction is the fact that due to the load on metal load bearing characteristics of metal roofs, or due to the changes in the weather which may cause thermal expansion or contraction, clips which are rigidly and are non-movably attached to roofing panels, can not accommodate this expansion and contraction or load bearing characteristic, and therefore tend to either break under the stress, or create warping or bending of the roof, which in turn would lead to breaks or gaps in the seams and would not be a completely moisture-proof roof.
One of the more recent types of clips that have been invented is claimed and disclosed in U.S. Pat. No. 4,796,403, entitled "Articulating Roofing Panel Clip". In this particular clip, there is provided a clip which attaches to a portion of a standing seam to a rigid purlin of a metal building, and which attempts to accommodate the movement of the roofing panels relative to the rigid purlin. The clip would include an upper support section for engaging a portion of the standing seam of roofing panels to attach the clip to the roofing panels. There would also be provided a rigid base for supporting the clip portion of the apparatus, and for anchoring the entire clip to the purlin. There would be further provided a third member which is disclosed as an articulated bearing member, which is positioned intermediate the upper clip portion and the rigid base for attempting to enable rotational and transnational articulation between the upper clip portion and the rigid base and purlin. There would be further provided a connector to connect the upper clip to the articulating bearing member and to connect the bearing member to the rigid base. As disclosed, a drawback to this particular type of clip is that the central articulating bearing member, is engaged to the lower base portion via a single threaded rivet, and therefore there is no allowance for translational or rotational movement between the base and the articulating member. Therefore, the only articulation and translational movement is between the clip portion and the articulating bearing member after that member has been rigidly attached to the base portion. Therefore, were one wish to permit the movement of the intermediate member relative to the movement of the clip, it would not do so, the only movement would be between the clip and the intermediate member.